>>Hello
>>
>>>Every relation, by definition, has a set of attributes
>>>whose values are unique, and which can therefore
>>>be used in relational expressions to uniquely identify
>>>a row. That's all you'd get out of a pointer. Further,
>>>by requiring the unnecessary pointer, you constrain
>>>implementations unnecessarily.
>>
>>But when I lose pointers I lose instance identity.

> > Yes. One of the biggest advantages of excluding pointers> from the model is that you lose instance identity, and all the> complexity that comes with it. This is particularly desirable> in a distributed context.

Instances of what, though? That is the question.

>>So It is impossible
>>or very dificult for some table to be a self row. It is not a deal for
>>me.
>>Also I lose possibility for some row to be contained by many tables.

Huh? What the hell does he suppose views do?

> These are just further consequences of the lack of instance identity.> > Also, I note that the things you're describing are features,> independent> of any problem context. Many problems admit to many different> techniques> for solving them. Simply heaping together features from OOPLs and> the relational model will not get you good design. There are> advantages> in learning how best to use each techinque on its own merits. Once> you have mastered that, you are in a much better position to consider> how two models might be integrated, or even whether that would be> a good idea.

One has to start at a very basic level asking why a feature exists in
the first place.
Received on Mon Mar 12 2007 - 15:40:50 CDT